Large Overhang

I am in the process of creating a 2 part mold for a client.
They have designed the parts for CNC lathe, because the parts are intended for casting wheels. These are prototypes.
The first attempt to print them resulted in a failure. The parts were too close together and partially filled some of what are cavities with a lot of resin.
These parts are medium size, my subjective opinion, and have several relatively large planar regions.

The result needs to be much closer to the original CAD file. Is there a way to calculate the compensation?
The first attempted parts were a little undersized, instead of the interior cavity being 52mm, the part measured about 51.6mm. The first print parts were oriented at an angle, but I think that the orientation of the open end of the mold, towards the basin of the resin tank caused major issues due to pressure/vacuum potential (which I just read about on this forum).

Ideally, support structures would not attach to the interior of the cavity of the mold.

If the parts were oriented such that the open ends of the molds are open to the build plate will there likely be an issue with overhang?
Or should the parts be built up directly from the build plate?

Thanks in advance for your assistance.

Are the cylinders closed at the top? Because that would trap resin inside and ruin your print.

Also I’ve never had good success printing parts with surfaces aligned flat with the build platform - setting them at a 20-25° angle has always worked much better and allowed resin to flow during the process.

Angling the parts is a good idea, because angled parts will need fewer supports on the flat surfaces (even if they need more supports on previously unsupported surfaces), and even with the tiny layer lines, angled surfaces will be much smoother and flatter between the supports.

With some experimentation, depending on the shape of your mold, you may be able to find an orientation that places very few supports on the inside of the part, and when you have some experience with printing, you may find that you can manually remove some supports. Sanding the support points with fine sandpaper may also make the surface smooth enough for your purposes.

You should check out our video on Part Orientation. Angling these will improve the surface finish and cleanup considerably and may help to address that dimensional issues you’re noticing.

As @rsandru mentioned, enclosed cavities leads to an effect called ‘cupping’ that can also cause dimensional issues and lead to poor surface finish. Are there any enclosed cavities in these models?

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